Harriet Dart is enjoying having her mum as her coach for the US Open and says the pair have only had one argument.

Dart made it into the second round at Flushing Meadows for the first time after disposing of Frenchwoman Chloe Paquet 6-1 6-2 on Monday.

With her regular coach Olga Morozova reluctant to travel outside the UK, Dart’s mum Susie stepped up in her absence for the American hard-court swing.

It brought instant results in New York, with Dart set to reach a provisional career high of 66.

“It’s a different dynamic, that’s for sure,” the 26-year-old said.

“We’ve only had one argument so that’s good. It’s just little things and I think it’s easier when it’s your mum because two minutes later you’re all fine.

“It’s been nice to have her, she knows me really well.

“She can hit with me a little bit and she’s played so she understands a lot of things and she’s been around Olga a lot, so it’s nice to have her around.

“She hasn’t been with me very much since I was a junior.

“She says her role is feeding balls, and throwing me balls, but there’s much more to it than that. She’s been helping me a lot.”

Ukrainian 19th seed Marta Kostyuk is waiting in the second round on Wednesday but there could be a problem if Dart can progress through that as her mum is a teacher and the new term is due to begin next week.

“She’s due to go back Friday, but we’ll see,” Dart said. “We’ll come to that when we need to.”

Earlier, Jan Choinski became the first British casualty after falling to an agonising five-set defeat to Roberto Carballes Baena.

Choinski, ranked 276 in the world, had earned himself a 100,000 dollar (£75,730) payday by coming through qualifying to earn a spot in the main draw at Flushing Meadows.

And he looked to be heading for a swift exit as he found himself two sets and a break down to the world number 55.

But the British number 10 rallied to send it to a decider, only for Carballes Baena to regain control and earn a 6-2 6-3 5-7 6-7 (5) 6-3 victory.